Connected: An Internet Encyclopedia
RFC 1042 - Header Format

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### Header Format

                                                                      Header

       ...--------+--------+--------+
                  MAC Header        |                        802.{3/4/5} MAC
       ...--------+--------+--------+

       +--------+--------+--------+
       | DSAP=K1| SSAP=K1| Control|                                802.2 LLC
       +--------+--------+--------+

       +--------+--------+---------+--------+--------+
       |Protocol Id or Org Code =K2|    EtherType    |            802.2 SNAP
       +--------+--------+---------+--------+--------+

The total length of the LLC Header and the SNAP header is 8-octets, making the 802.2 protocol overhead come out on an nice boundary.

The K1 value is 170 (decimal).

The K2 value is 0 (zero).

The control value is 3 (Unnumbered Information).

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Connected: An Internet Encyclopedia
RFC 1042 - Header Format